freopen.cpp File Reference

#include <corecrt_internal_stdio.h>

Include dependency graph for freopen.cpp:

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Functions
template<typename Character >
static errno_t __cdecl	common_freopen (FILE **const result, Character const *const file_name, Character const *const mode, __crt_stdio_stream const stream, int const share_flag) throw ()
FILE *__cdecl	freopen (char const *const file_name, char const *const mode, FILE *const public_stream)
errno_t __cdecl	freopen_s (FILE **const result, char const *const file_name, char const *const mode, FILE *const public_stream)
FILE *__cdecl	_wfreopen (wchar_t const *const file_name, wchar_t const *const mode, FILE *const public_stream)
errno_t __cdecl	_wfreopen_s (FILE **const result, wchar_t const *const file_name, wchar_t const *const mode, FILE *const public_stream)

Function Documentation

_wfreopen()

FILE *__cdecl _wfreopen	(	wchar_t const *const	file_name,
		wchar_t const *const	mode,
		FILE *const	public_stream
	)

Definition at line 110 of file freopen.cpp.

{
    FILE* result_stream = nullptr;
    common_freopen(&result_stream, file_name, mode, __crt_stdio_stream(public_stream), _SH_DENYNO);
    return result_stream;
}

_wfreopen_s()

errno_t __cdecl _wfreopen_s	(	FILE **const	result,
		wchar_t const *const	file_name,
		wchar_t const *const	mode,
		FILE *const	public_stream
	)

Definition at line 121 of file freopen.cpp.

{
    return common_freopen(result, file_name, mode, __crt_stdio_stream(public_stream), _SH_SECURE);
}

common_freopen()

template<typename Character >

static errno_t __cdecl common_freopen ( FILE **const  result, Character const *const  file_name, Character const *const  mode, __crt_stdio_stream const  stream, int const  share_flag  ) throw ( )

static

Definition at line 21 of file freopen.cpp.

{
    typedef __acrt_stdio_char_traits<Character> stdio_traits;
 
    _VALIDATE_RETURN_ERRCODE(result != nullptr, EINVAL);
    *result = nullptr;
 
    // C11 7.21.5.4/3:  "If filename is a null pointer, the freopen function
    // attempts to change the mode of the stream to that specified by mode, as
    // if the name of the file currently associated with the stream had been
    // used. It is implementation-defined which changes of mode are permitted
    // (if any), and under what circumstances."
    //
    // In our implementation, we do not currently support changing the mode
    // in this way.  In the future, we might consider use of ReOpenFile to
    // implement support for changing the mode.
    _VALIDATE_RETURN_ERRCODE_NOEXC(file_name != nullptr, EBADF);
 
    _VALIDATE_RETURN_ERRCODE(mode      != nullptr, EINVAL);
    _VALIDATE_RETURN_ERRCODE(stream.valid()      , EINVAL);
 
    // Just as in the common_fsopen function, we do not hard-validate empty
    // 'file_name' strings in this function:
    _VALIDATE_RETURN_ERRCODE_NOEXC(*file_name != 0, EINVAL);
 
    errno_t return_value = 0;
 
    _lock_file(stream.public_stream());
    __try
    {
        // If the stream is in use, try to close it, ignoring possible errors:
        if (stream.is_in_use())
            _fclose_nolock(stream.public_stream());
 
        stream->_ptr  = nullptr;
        stream->_base = nullptr;
        stream->_cnt  = 0;
        stream.unset_flags(-1);
 
        // We may have called fclose above, which will deallocate the stream.
        // We still hold the lock on the stream, though, so we can just reset
        // the allocated flag to retain ownership.
        stream.set_flags(_IOALLOCATED);
 
        *result = stdio_traits::open_file(file_name, mode, share_flag, stream.public_stream());
        if (*result == nullptr)
        {
            stream.unset_flags(_IOALLOCATED);
            return_value = errno;
        }
    }
    __finally
    {
        _unlock_file(stream.public_stream());
    }
    __endtry
 
    return return_value;
}

Referenced by _wfreopen(), _wfreopen_s(), freopen(), and freopen_s().

freopen()

FILE *__cdecl freopen	(	char const *const	file_name,
		char const *const	mode,
		FILE *const	public_stream
	)

Definition at line 89 of file freopen.cpp.

{
    FILE* result_stream = nullptr;
    common_freopen(&result_stream, file_name, mode, __crt_stdio_stream(public_stream), _SH_DENYNO);
    return result_stream;
}

freopen_s()

errno_t __cdecl freopen_s	(	FILE **const	result,
		char const *const	file_name,
		char const *const	mode,
		FILE *const	public_stream
	)

Definition at line 100 of file freopen.cpp.

{
    return common_freopen(result, file_name, mode, __crt_stdio_stream(public_stream), _SH_SECURE);
}